Four more dissidents have been arrested in Eritrea, bringing to at least 11 the number of former senior government officials detained this week, a western source contacted from Nairobi told AFP on Thursday.

The status of a twelfth person, former defense minister Mesfin Hagos, was not clear, said the source, who asked not to be named.

Mesfin was abroad when the first arrests were made on Tuesday but has since returned to Eritrea.

All these people, who include several other former ministers, were among 15 top government officials who since May have openly criticized the government of President Issaias Afeworki, accusing him of being autocratic, and called for democratic reforms.

In May, the 15 put their names to a letter highly critical of the president.

The arrests began on Tuesday. Independent newspapers in Eritrea have been suspended.

The government has said nothing publicly about these developments.

The dissidents also include Haile Menkerios, Eritrea's former ambassador to the United Nations, where he now presides the committee responsible for sanctions against Afghanistan.

The western source in Asmara told AFP that one of the 15 signatories of the May letter who is still in Eritrea had not been arrested as of Thursday. Yet another is abroad.

The French press rights group Reporters sans Frontieres (RSF) has issued a statement condemning the closure of eight private newspapers, saying this was "unacceptable and an impediment to the establishment of democracy in Eritrea" where the first legislative elections are in theory due to be held in December.

"Nobody has seen such a radical and repressive act against the private press in Africa for many years," RSF said in a statement and an open letter to Issaias, describing him as "a predator of press freedom.

RSF reported that the director of state television had gone air to accuse the newspapers of putting "the unity of the country at risk".

It noted that the move came at a time when the private press was for the first time outselling the official press -- NAIROBI (AFP)